5 #include "heuristical.h"
6 #include "html_dumper.h"
10 #include "pbqp_edge_t.h"
11 #include "pbqp_node.h"
12 #include "pbqp_node_t.h"
15 static pbqp_edge **edge_bucket;
16 static pbqp_node **node_buckets[4];
17 static pbqp_node **reduced_bucket = NULL;
18 static int buckets_filled = 0;
20 static num add(num x, num y)
22 if (x == INF_COSTS || y == INF_COSTS) return INF_COSTS;
27 static void init_buckets(void)
31 edge_bucket = NEW_ARR_F(pbqp_edge *, 0);
32 reduced_bucket = NEW_ARR_F(pbqp_node *, 0);
34 for (i = 0; i < 4; ++i) {
35 node_buckets[i] = NEW_ARR_F(pbqp_node *, 0);
39 static void fill_node_buckets(pbqp *pbqp)
45 node_len = pbqp->num_nodes;
47 for (node_index = 0; node_index < node_len; ++node_index) {
49 pbqp_node *node = get_node(pbqp, node_index);
53 arity = ARR_LEN(node->edges);
55 /* We have only one bucket for nodes with arity >= 3. */
60 node->bucket_index = ARR_LEN(node_buckets[arity]);
62 ARR_APP1(pbqp_node *, node_buckets[arity], node);
68 static void normalize_towards_source(pbqp *pbqp, pbqp_edge *edge)
87 src_vec = src_node->costs;
88 tgt_vec = tgt_node->costs;
92 src_len = src_vec->len;
93 tgt_len = tgt_vec->len;
100 /* Normalize towards source node. */
101 for (src_index = 0; src_index < src_len; ++src_index) {
102 num min = pbqp_matrix_get_row_min(mat, src_index, tgt_vec);
105 pbqp_matrix_sub_row_value(mat, src_index, tgt_vec, min);
106 src_vec->entries[src_index].data = add(
107 src_vec->entries[src_index].data, min);
109 // TODO add to edge_list if inf
114 static void normalize_towards_target(pbqp *pbqp, pbqp_edge *edge)
128 src_node = edge->src;
129 tgt_node = edge->tgt;
133 src_vec = src_node->costs;
134 tgt_vec = tgt_node->costs;
138 src_len = src_vec->len;
139 tgt_len = tgt_vec->len;
146 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
147 num min = pbqp_matrix_get_col_min(mat, tgt_index, src_vec);
150 pbqp_matrix_sub_col_value(mat, tgt_index, src_vec, min);
151 tgt_vec->entries[tgt_index].data = add(
152 tgt_vec->entries[tgt_index].data, min);
154 // TODO add to edge_list if inf
159 static void reorder_node(pbqp_node *node)
163 unsigned old_bucket_len;
165 if (!buckets_filled) return;
169 arity = ARR_LEN(node->edges);
171 /* Equal bucket as before */
172 if (arity > 2) return;
174 /* Assume node lost one incident edge. */
175 old_arity = arity + 1;
177 if (ARR_LEN(node_buckets[old_arity]) <= (int)node->bucket_index
178 || node_buckets[old_arity][node->bucket_index] != node) {
179 /* Old arity is new arity, so we have nothing to do. */
183 old_bucket_len = ARR_LEN(node_buckets[old_arity]);
184 assert (node_buckets[old_arity][node->bucket_index] == node);
186 /* Delete node from old bucket... */
187 node_buckets[old_arity][old_bucket_len - 1]->bucket_index
188 = node->bucket_index;
189 node_buckets[old_arity][node->bucket_index]
190 = node_buckets[old_arity][old_bucket_len - 1];
191 ARR_SHRINKLEN(node_buckets[old_arity], (int)old_bucket_len - 1);
193 /* ..and add to new one. */
194 node->bucket_index = ARR_LEN(node_buckets[arity]);
195 ARR_APP1(pbqp_node *, node_buckets[arity], node);
198 static void simplify_edge(pbqp *pbqp, pbqp_edge *edge)
211 src_node = edge->src;
212 tgt_node = edge->tgt;
216 if(pbqp->dump_file) {
218 sprintf(txt, "Simplification of Edge n%d-n%d", src_node->index, tgt_node->index);
219 dump_section(pbqp->dump_file, 3, txt);
222 src_vec = src_node->costs;
223 tgt_vec = tgt_node->costs;
227 src_len = src_vec->len;
228 tgt_len = tgt_vec->len;
235 if (pbqp->dump_file) {
236 fputs("Input:<br>\n", pbqp->dump_file);
237 dump_simplifyedge(pbqp, edge);
240 normalize_towards_source(pbqp, edge);
241 normalize_towards_target(pbqp, edge);
243 if (pbqp->dump_file) {
244 fputs("<br>\nOutput:<br>\n", pbqp->dump_file);
245 dump_simplifyedge(pbqp, edge);
248 if (pbqp_matrix_is_zero(mat, src_vec, tgt_vec)) {
249 if (pbqp->dump_file) {
250 fputs("edge has been eliminated", pbqp->dump_file);
253 reorder_node(src_node);
254 reorder_node(tgt_node);
259 void solve_pbqp_heuristical(pbqp *pbqp)
266 if (pbqp->dump_file) {
267 pbqp_dump_input(pbqp);
268 dump_section(pbqp->dump_file, 1, "2. Simplification of Cost Matrices");
271 node_len = pbqp->num_nodes;
275 /* First simplify all edges. */
276 for (node_index = 0; node_index < node_len; ++node_index) {
278 pbqp_node *node = get_node(pbqp, node_index);
285 edge_len = ARR_LEN(edges);
287 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
288 pbqp_edge *edge = edges[edge_index];
290 /* Simplify only once per edge. */
291 if (node_index != edge->src->index) continue;
293 simplify_edge(pbqp, edge);
297 /* Put node into bucket representing their arity. */
298 fill_node_buckets(pbqp);
301 if (ARR_LEN(edge_bucket) > 0) {
302 panic("Please implement edge simplification");
303 } else if (ARR_LEN(node_buckets[1]) > 0) {
305 } else if (ARR_LEN(node_buckets[2]) > 0) {
306 panic("Please implement RII simplification");
307 } else if (ARR_LEN(node_buckets[3]) > 0) {
308 panic("Please implement RN simplification");
314 if (pbqp->dump_file) {
315 dump_section(pbqp->dump_file, 1, "4. Determine Solution/Minimum");
316 dump_section(pbqp->dump_file, 2, "4.1. Trivial Solution");
319 /* Solve trivial nodes and calculate solution. */
320 node_len = ARR_LEN(node_buckets[0]);
321 for (node_index = 0; node_index < node_len; ++node_index) {
322 pbqp_node *node = node_buckets[0][node_index];
325 node->solution = vector_get_min_index(node->costs);
326 pbqp->solution = add(pbqp->solution,
327 node->costs->entries[node->solution].data);
328 if (pbqp->dump_file) {
329 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
330 dump_node(pbqp, node);
334 if (pbqp->dump_file) {
335 dump_section(pbqp->dump_file, 2, "Minimum");
336 fprintf(pbqp->dump_file, "Minimum is equal to %d.", pbqp->solution);
337 dump_section(pbqp->dump_file, 2, "Back Propagation");
340 /* Solve reduced nodes. */
341 node_len = ARR_LEN(reduced_bucket);
342 for (node_index = node_len; node_index > 0; --node_index) {
343 pbqp_node *node = reduced_bucket[node_index - 1];
346 switch (ARR_LEN(node->edges)) {
348 back_propagate_RI(pbqp, node);
351 panic("Please implement back propagation for RII");
354 panic("Only nodes with degree one or two should be in this bucket");
360 void applyRI(pbqp *pbqp)
362 pbqp_node **bucket = node_buckets[1];
363 unsigned bucket_len = ARR_LEN(bucket);
364 pbqp_node *node = bucket[bucket_len - 1];
365 pbqp_edge *edge = node->edges[0];
366 pbqp_matrix *mat = edge->costs;
367 int is_src = edge->src == node;
368 pbqp_node *other_node;
371 other_node = edge->tgt;
373 other_node = edge->src;
376 if (pbqp->dump_file) {
378 sprintf(txt, "RI-Reduktion of Node n%d", node->index);
379 dump_section(pbqp->dump_file, 2, txt);
380 pbqp_dump_graph(pbqp);
381 fputs("<br>\nBefore reduction:<br>\n", pbqp->dump_file);
382 dump_node(pbqp, node);
383 dump_node(pbqp, other_node);
384 dump_edge(pbqp, edge);
388 pbqp_matrix_add_to_all_cols(mat, node->costs);
389 normalize_towards_target(pbqp, edge);
391 pbqp_matrix_add_to_all_rows(mat, node->costs);
392 normalize_towards_source(pbqp, edge);
394 disconnect_edge(other_node, edge);
396 if (pbqp->dump_file) {
397 fputs("<br>\nAfter reduction:<br>\n", pbqp->dump_file);
398 dump_node(pbqp, other_node);
401 /* Remove node from bucket... */
402 ARR_SHRINKLEN(bucket, (int)bucket_len - 1);
403 reorder_node(other_node);
405 /* ...and add it to back propagation list. */
406 node->bucket_index = ARR_LEN(reduced_bucket);
407 ARR_APP1(pbqp_node *, reduced_bucket, node);
410 void applyRII(pbqp *pbqp)
412 pbqp_node **bucket = node_buckets[1];
413 unsigned bucket_len = ARR_LEN(bucket);
414 pbqp_node *node = bucket[bucket_len - 1];
415 pbqp_edge *src_edge = node->edges[0];
416 pbqp_edge *tgt_edge = node->edges[1];
417 int src_is_src = src_edge->src == node;
418 int tgt_is_src = tgt_edge->src == node;
419 pbqp_matrix *src_mat;
420 pbqp_matrix *tgt_mat;
435 src_node = src_edge->tgt;
437 src_node = src_edge->src;
441 tgt_node = tgt_edge->tgt;
443 tgt_node = tgt_edge->src;
446 /* Swap nodes if necessary. */
447 if (tgt_node->index < src_node->index) {
459 src_is_src = src_edge->src == node;
460 tgt_is_src = tgt_edge->src == node;
463 src_mat = src_edge->costs;
464 tgt_mat = tgt_edge->costs;
466 src_vec = src_node->costs;
467 tgt_vec = tgt_node->costs;
468 node_vec = node->costs;
470 row_len = ARR_LEN(src_vec);
471 col_len = ARR_LEN(tgt_vec);
472 node_len = ARR_LEN(node_vec);
474 mat = pbqp_matrix_alloc(pbqp, row_len, col_len);
476 for (row_index = 0; row_index < row_len; ++row_index) {
477 for (col_index = 0; col_index < col_len; ++col_index) {
478 vec = vector_copy(pbqp, node_vec);
481 vector_add_matrix_col(vec, src_mat, row_index);
483 vector_add_matrix_row(vec, src_mat, row_index);
487 vector_add_matrix_col(vec, tgt_mat, col_index);
489 vector_add_matrix_row(vec, tgt_mat, col_index);
492 mat->entries[row_index * col_len + col_index] = vector_get_min_index(vec);
496 pbqp_edge *edge = get_edge(pbqp, src_node->index, tgt_node->index);
499 edge = alloc_edge(pbqp, src_node->index, tgt_node->index, mat);
501 pbqp_matrix_add(edge->costs, mat);
503 /* Free local matrix. */
504 obstack_free(&pbqp->obstack, mat);
507 /* Disconnect node. */
508 disconnect_edge(src_node, src_edge);
509 disconnect_edge(tgt_node, tgt_edge);
511 /* Edge has changed so we simplify it. */
512 simplify_edge(pbqp, edge);
515 void back_propagate_RI(pbqp *pbqp, pbqp_node *node)
526 edge = node->edges[0];
528 is_src = edge->src == node;
534 vector_add_matrix_col(vec, mat, other->solution);
538 vector_add_matrix_row(vec, mat, other->solution);
541 node->solution = vector_get_min_index(vec);
542 if (pbqp->dump_file) {
543 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
547 int node_is_reduced(pbqp_node *node)
549 if (!reduced_bucket) return 0;
552 if (ARR_LEN(node->edges) == 0) return 1;
554 unsigned bucket_length = ARR_LEN(reduced_bucket);
555 unsigned bucket_index = node->bucket_index;
557 return bucket_index < bucket_length && reduced_bucket[bucket_index] == node;